Planet of Origin: Okaara (Vega 13)
Okaarans were humanoids who developed a gentle, life cherishing civilization on the then Earthlike planet Okaara. Their peace was shattered by the arrival of the Psions, who abducted and experimented on them. Soon their planet became a nuclear holocaust. Those who survived tunneled deep into the barren soil, making their homes in vast chambers and tunnels. Radiation changed the forms of the blue-skinned species, making them the stocky and fang-toothed. Their civilization survived, and even though they vowed to fight no more wars, they studied and perfected the arts of combat. As civilization spread through the Vegan system, the Okaarans observed and sent emissaries, often establishing their religion on other worlds. Okaara became a place of learning, and favored students from other worlds came there to pursue both physical and mental excellence. Okaaran combat training was particularly valued.
Many millennia ago, some okaarans were brought to Tamaran, most probably by the Psions. Their skin changed from blue to gold. As they made the world their own, the Tamarans established a planetary government that evolved into a feudal society. Each landmass was ruled by a royal family, under the dominion of which exist smaller city-states ruled by Influential families. Passionate people driven more by emotion than reason, they are unusually fierce warriors, but their capacity for love is even greater than their capacity for hate; as a result, war and strife were for many centuries long forgotten on Tamaran. Instead, the people channeled their energies into creating a tropical utopia, a paradise where they could live in harmony with the wildlife and where battle skills were maintained largely for ceremony's sake. Unfortunately, with the rise in power of the Citadelians, Tamaran was eventually reintroduced to war. Tamaran re-ouffitted its armies and managed to lend off a Citadelian invasion for more than an Earth century. In the ensuing battle, millions of Tamaraneans were killed; the entire race would have been annihilated had not King ruefully negotiated a solemn truce, the signature of which involved sacrificing his daughter to the slavers of the Citadel. Despite this truce, Tamaran's troubles were far from over. The citizens instigated a worldwide civil war. While the Tamaran fleet fought valiantly, they were overwhelmed. Knowing they couldn't stop the Psions. They called for an evacuation plan, to save as many Tamarans as possible. The attack by the Psions caused the planet’s core of Tamaran to implode.
Many Tamarans were off-world during the explosion – enough to settle on a new planet dubbed New Tamaran. When the Sun Eater ravaged the galaxy, New Tamaran lay in its path and was destroyed along with many of the remaining Tamarans.
A group of Tamarans were off-world during the explosion of New Tamaran. Seeking a new home, they lead an invasion on the planet Karna, home of the Gordanians. After a short conflict, The Gordanians allowed them to stay; in exchange, the Tamarans tought them new trades outside of slavery. Shortly afterward, tragedy struck, a series of Imperiex probes destroyed Karna.
The Psions experiments on the Okaarans also lead to the creation of the Citadelians. The first Citadellian rebelled against his creators and used their machinery to clone himself, creating the Citadel race, but the clones were imperfect and retarded. The citadellians started war against all neighboring worlds in the Vega system. They were demented madmen who held power through brute force and fear but their time would be limited and the great Citadel empire quickly collapsed. Though the back of the empire was broken, but many of the weapons, machines, and warriors remained.
Source: DC Universe "New Teen Titans"